Dear G,
You are absolutely correct that this is a Bark Gnawing Beetle in the genus Temnoscheila as the images on BugGuide will verify. BugGuide also notes: “can inflict a painful bite if handled carelessly.”

Subject: Unknown Bug at Yale BC
Location: Yale, BC
April 18, 2015 9:10 pm
My friend sent me this photo of a scarlet bug on his fire pit at Yale, BC but I have been unable answer his question as to what it is. I am sure I have seen it myself many years ago, but have not been able to find reference to it on the internet.
Signature: James

Red Flat Bark Beetle

Dear James,
This looks like a Red Flat Bark Beetle, Cucujus clavipes, and we suspect is was living on some wood your friend was going to burn in the fire pit. According to Your Piece of the Planet: “The Red Flat Bark Beetle, Cucujus clavipes, is typically found under the bark of ash and poplar. Its flat shape allows it to easily move around under bark, and sometimes even into the tunnels of destructive wood borers and bark beetles, which it likes to eat. This is beneficial, as it helps limit wood borer and bark beetle damage to the tree.”

Subject: Temnoscheila
Location: Wichita Falls, Texas
May 30, 2014 2:46 pm
We have identified the green beetles on one of our red oak trees as temnoscheila.
We used a tree drench on it a few days ago to systemically rid the tree of the beetles, which are gnawing holes in the bark and making it fall off. But drench can take up to three months to work. Is there anything else you would recommend to help us? We don’t want to lose the tree.
We live in Wichita Falls, Texas, and are in a bad drought. We have been watering the trees with pond water, since we are not allowed to use city water on the yard.
We don’t see the beetles on any other trees (hope they don’t spread). Thanks.
I hope I sent the right picture of the beetles and not my dogs.
Signature: Ercie Hill

Metallic Green Bark Gnawing Beetle

Dear Ercie,
We are very excited to be able to post your image of this beautiful species that helps to return trees to humus. We took the liberty of cropping and correcting your image of a Bark Gnawing Beetle.The BugGuide page on the genus is a beautifully designed page.

Temnoscheila species

Daniel, thank you. Sorry my image was not better. My camera doesn’t take very good close-up photos.
Any idea why the beetles are on the oak tree and how to talk them into going somewhere else?
Thanks again,
Ercie Hill

We have very good news for you Ercie, sort of. We just received a complimentary copy of Arthur V. Evans’ new book, Beetles of Eastern North America, and here is what he has to say about Temnoscheila virescens: “Adults and larvae found in pines infested with bark beetles and are important predators of Dendroctonus. Adults prey on adult bark beetles, while their larvae consume Dendroctonus eggs and larvae.” According to BugGuide, Dendroctonus: “Breed on boles of conifers; sometimes kill healthy trees.” So, you have photographed the predator, not the problem. We would urge you not to take any action against this magnificent Bark Gnawing Beetle, even though its family name is deceptive. It is feeding on the beetle that is the problem. The material we are citing lists pines as the trees affected by the Bark Beetle, but that is not to say that the Bark Gnawing Temnoscheila might also prey on Bark Beetles that affect other trees, namely, your oak.

Daniel, thank you. We’ve seen these beetles around here as long as I can remember, just never saw them on a tree. I appreciate your responses – thanks so much.
Ercie

Subject: Cucujus clavipes
Location: Wellington, Colorado
September 22, 2012 10:48 pm
I decided to do some bug searching with one of my three sons today and it ended being all four of us. We have an old cottonwood stump that I cut down and we decided to pull away some of the bark to see what was going on. Upon pulling it off and getting past the centipedes, we saw two very unique beetles. One I was able to identify using bug guide!http://bugguide.net/node/view/494540
So I’m submitting my pictures as I haven’t seen them on What’s that bug for a while.
Signature: Fish Seal

Flat Red Bark Beetles

Dear Fish Seal,
Thanks for submitting your images of Red Flat Bark Beetles, Cucujus clavipes. We have not posted a new image of the species since 2010.The Florida State Collection of Arthropods has some additional information on the family. It seems like your images were reduced in size and resolution. We can easily accept images with a higher resolution in order to provide the highest quality for our readership.

Flat Red Bark Beetle

Daniel,
I’m sorry about how the pictures came through. I have attached the full pictures.

Thanks. We are making a swap, but that takes additional time. Please submit full size files in the future.

Emerald ash borer?
Location: Annapolis, Maryland
December 19, 2011 8:54 am
Hi, I found this insect while chopping wood. At first I was concerned that it was an emerald ash borer as it is the right size (14mm long) and shape. It’s head, especially the eyes and mandibles look quite different though.
It was dead when I found it, seemed to be attached to the wood by its rear end.
Thanks!
Signature: ash borer?

Bark Gnawing Beetle: Temnoscheila species

Dear ash borer?,
You are correct that this is not an Emerald Ash Borer, Agrilus planipennis, which is nicely represented in this excellent online pdf prepared by Gary L. Parsons of the Michigan State University Department of Entomology. On page 55 of that pdf, we located a Bark Gnawing Beetle, Temnoscheila virescens that appears to match your beetle. It is described as: “Length: 8.6-17.8 mm, slightly larger than EAB. Color bright green or blue-green varying to almost dark purplish-blue, often with brassy reflections. Head large, prognathous, and more evident than in Buprestidae, and the connection of the pronotum to mesothorax is narrowed, waist-like. T. virescens occurs in the eastern U.S. with T. chlorodia (Mannerhiem), a very similar species, occurring in the western North America. Both species are predators found under the bark of dead trees where they feed on a variety of woodboring beetles.” That Bark Gnawing Beetle can also be found on BugGuidealong with several other members of the genus.